1. Field of the Invention
The present invention pertains to latching mechanisms for securing a removable closure frame, such as a window screen, against a second relatively fixed closure frame, such as a window frame or a door frame, particularly a window unit of the louver type.
2. Description of the Prior Art
It is well-known in the prior art to have window and door systems wherein the window or door closure frame accepts removable closure frames holding screening material or glass. The removable closure frames typically are positioned in the window or door frame and latching mechanisms are activated to secure the removable closure frame against the fixed closure frame. Such systems, of course, allow for the convenient replacement of glassed windows and doors with screening material during periods of warm weather and vice versa during colder months of the year.
It is conventional to secure the removable closure frames to the closure frame of the door or window using plate elements held eccentrically by screws or bolts installed concurrently with the replaceable closure frame. The screws or bolts are tightened sufficiently to produce a "wedging" or "clamping" force on the edge of the removable closure frame. Prior art latching systems are known wherein eccentric latching plates fixed to shafts are rotatably mounted on the closure frame, to be activated to a locking position by rotation of the shaft element relative to the frame.
Problems with latching mechanisms utilizing removable screws and latching plates are self-evident. An individual latching component can be dropped and become lost during installation, thereby causing undue delay or the use of less than a satisfactory number of latches due to the unavailability of a replacement part. The problems associated with latching mechanisms having latching plates fixed to shafts rotating within the closure frame include binding of the shaft in the frame, thus rendering the latch inoperable, or requiring an inordinate amount of effort to latch, and can lead to frustration an even injury of the installer and increased costs during normal maintenance procedures such as window cleaning. This problem is particularly prevelant in the use of aluminum closure frames and aluminum bolt materials which are susceptible to both galling and corrosion due to the weather.